With the rapid development of industries such as electric tools, home appliances, electric vehicles, drones, etc., motors are constantly upgrading with the goal of smaller size, higher efficiency, and stronger reliability. Inside a motor, the Motor Coil Fixing Adhesive, although inconspicuous, is a key material that affects the lifespan, stability, and safety of the motor.
Today, we will start from a popular science perspective and explain in an article:
Why do motor coils have to use adhesive?
What are the common types of motor adhesives?
How to choose the one that suits your motor?
What is the latest trend in adhesive usage in the industry?
1、 Why do motor coils need to be fixed and bonded?
In environments with high-speed rotation, high temperature, and high vibration, motor coils will face: Strong vibration impact
Once the coil becomes loose, it can cause noise, unstable magnetic field, decreased efficiency, and even lead to short circuits.
- High temperature thermal aging
The winding is exposed to 120-180 ° C for a long time, and ordinary glue is easy to harden, break, and fail. - Strict insulation requirements
Reliable dielectric strength must be maintained between coils to avoid electrical breakdown. - Erosion caused by environmental factors
Moisture, dust, and oil stains can all shorten the lifespan of the motor.
Therefore, the coil fixing adhesive not only needs to be adhesive, resistant to high temperatures and vibrations, but also has comprehensive abilities such as insulation, oil resistance, moisture resistance, and cracking prevention. It can be said that the coil fixing adhesive is the “invisible guard” for the stable operation of the motor.
2、 What are the types of adhesive used to fix motor coils?
The demand for adhesive varies greatly among motors of different industries and powers. The mainstream adhesive types include:
① Epoxy Adhesive
Features:
High strength, high temperature resistance, very hard after curing, and stable long-term insulation performance.
Suitable scenarios:
High power motors, automotive motors, industrial motors, and motor systems that operate at high temperatures for a long time.
Advantage:
Temperature resistance up to 155-180 ° C
High structural strength and good fatigue performance
Long term insulation is reliable and will not decay due to environmental changes
High hardness after curing, suitable for withstanding slot wedge thrust and coil expansion force
Typical applications:
Stator slot wedge bonding, coil structure fixation, magnetic tile bonding, skeleton reinforcement.
Recommended products by Yilian:
EP 1738: High strength single component epoxy, suitable for stator slot wedges, coil fixation, and high-temperature magnetic tile bonding
EP 1761: Used for bonding wire harnesses, motor magnets, and metal structures
EP 2025 FR: Fast curing two-component epoxy, suitable for automated dispensing and high-efficiency production lines
② Addition Cure Silicone
Features:
Good flexibility, high and low temperature resistance, strong seismic resistance, very suitable for absorbing vibration and impact.
Suitable scenarios:
High speed motors, drone motors, small precision motors, high-speed rotor systems.
Advantage:
-50 ° C to 200 ° C ultra wide temperature stability
Soft and not brittle, not easy to crack
Excellent buffering performance in high vibration and high-speed motors
Suitable for coil surface encapsulation and buffering fixation
Typical applications:
High speed rotor fixation, coil assisted buffering, speed regulator and winding protection.
Recommended products by Yilian:
SIPA 1850/A/B: two-component addition molding silicone, fast curing, suitable for filling and fixing motor coils
SIPA 1820: Soft and resistant to thermal shock, used for bonding and protecting the internal structure of high-speed motors
③ Acrylic Adhesive
Features:
The curing speed is extremely fast, suitable for consumer motors that require quick assembly.
Suitable scenarios:
Small power motors, electric toy motors, fan motors, and consumer electronics rotor structures.
Advantage:
Rapid solidification greatly improves production line efficiency
Good strength and low cost
Suitable for various composite materials such as plastic metal
Shortcoming:
The temperature resistance is not as good as epoxy and silicone, making it unsuitable for high-temperature motors.
Typical applications:
Small rotor fixation, plastic bracket bonding, and rapid assembly of motor terminal structure.
Recommended products by Yilian:
MA 1012: Fast setting acrylic structural adhesive, suitable for fast positioning and structural bonding of consumer motors
MA series (customized): can be used for rapid curing applications of plastic metal hybrid structures
④ Polyurethane Adhesive
Features:
Excellent flexibility and strong material adaptability, especially suitable for scenarios that require certain buffering and impact resistance.
Suitable scenarios:
Motor end cover bonding, winding auxiliary fixation, lightweight structure bonding, motor housing sealing.
Advantage:
High elasticity, capable of absorbing impact
Good adhesion to multiple materials such as plastic, metal, rubber, etc
Reliable seismic performance
Shortcoming:
The stability of epoxy is not as good as that of high-power motors/continuous high temperatures.
Typical applications:
End cap bonding, winding auxiliary positioning, and structural components that require flexibility in working conditions.
Recommended products by Yilian:
PUR 1680 A/B (D70 hardness): High hardness polyurethane structural adhesive, suitable for bonding motor end caps and fixing windings
PUR series customized models: suitable for structural fixation applications with flexible cushioning
3、 Typical application scenarios and adhesive solutions
① Small motors (fans, household appliances, toy motors)
Requirement: Fast curing, low cost
Recommendation: Acrylic adhesive/room temperature curing epoxy adhesive
② Medium and large industrial motors, pump motors
Requirements: High strength, temperature resistance, insulation
Recommendation: High temperature epoxy structural adhesive
③ High speed motors (drone motors, small power motors)
Requirements: Flexibility, shock resistance, high speed resistance
Recommendation: Addition molding silicone elastic adhesive
④ Automotive motors (drive motors, EPS, OBC internal fans)
Requirements: Oil resistant, temperature resistant, salt spray resistant, UL/automotive grade certification
Recommendation: High temperature resistant epoxy adhesive/high-performance silicone adhesive
No matter how advanced the motor design is, if the coil becomes loose, insulation decreases, or glue peels off at high temperatures, it will directly affect the service life and stability. Therefore, choosing the appropriate adhesive for fixing motor coils is not a cost issue, but a reliability issue.
Engineers can make comprehensive judgments from multiple dimensions such as temperature resistance, earthquake resistance, insulation, safety certification, and process adaptation to ensure the long-term stable operation of motors.
